Every day is routine for deployed U.S. troops. They pull duty, maintain their gear, and they go on patrol — day in and day out — until all hell breaks loose and a world of insurgents are trying to kill them.

When that happens, the SAW can effectively blanket an area with up to 120 rounds per minute. That's two 5.56mm bullets slipping from the barrel every second — fed from a 200 round belt — inside a quick-change drum.

Troops call it a "Wall of Steel" that has saved more American lives than they can count.

When it works.

The SAW is flawed: Parts break off, it's hard to clean, it jams, and like all machine guns it overheats to the point of uselessness, and changing the barrel isn't always an option.

But like an old cellphone we keep until the plan renews, the SAW is what U.S. troops have until something better comes along.

The following slides are from a firefight with a U.S. Army unit at Combat Outpost Charkh in Afghanistan, and some infrared shots at an indoor range.